Cervical cancer, genital warts, and other health conditions associated with human papillomavirus (HPV) exact substantial morbidity, mortality, and expenses. In 2006, the Food and Drug Administration (FDA) approved a quadrivalent HPV vaccine for females ages 9-26, and the Advisory Committee on Immunization Practices (ACIP) recommended routine vaccination for girls ages 11-12. Modest vaccination rates to date, however, indicate problems with increasing coverage and adherence to the recommended vaccine schedule, and may presage difficulties in realizing the vaccine's public health promise. Provider-oriented issues and challenges related to vaccine implementation may have been underestimated and remain insufficiently studied, especially with regard to primary care physicians (PCPs), who are well suited to provide vaccine to most young females. The broad objective of this study is to identify the appropriate constellation of factors that differentially relate to clinicians'stated intentions to administer HPV vaccine as recommended. Our central hypothesis is that clinicians'attitudes, subjective norms, and perceptions of issues as barriers significantly influence their intentions to administer the vaccine and, ultimately, their behavior, as predicted by the theory of planned behavior (TPB). We propose four specific aims: 1) to develop a theoretically-informed survey questionnaire for the assessment of TPB-based and other measures of PCPs'intentions to administer the HPV vaccine;2) to implement the survey questionnaire among PCPs in Alabama and Mississippi;3) to examine PCP characteristics and TPB-based measures regarding intention to administer HPV vaccine under different conditions;and 4) to identify groups of PCPs who can be differentiated with respect to the patterns of functional relations between the TPB-factors and intentionality. Using nominal group technique meetings and other steps, the survey instrument will be developed, pre-tested and piloted with PCPs and family practice residents and faculty. At least 300 complete survey responses will be collected from PCPs to allow examination of our hypotheses and relationships between relevant variables and intentionality under different patient conditions. Intentionality will be operationalized through a series of behaviorally anchored case vignettes. PCPs'awareness and attitudes regarding ACIP recommendations will also be evaluated. The study will be administered in two states with high HPV-associated disease burdens, acute PCP shortages, and low HPV immunization rates. The proposed research will yield important information to improve understanding of theoretical predictors and provider-based barriers to HPV vaccination in actual practice. This should also suggest useful direction for developing provider-based strategies to increase the likelihood of vaccine administration that could be studied in future research. PUBLIC HEALTH RELEVANCE: HPV vaccination offers an effective prevention strategy for reducing the substantial morbidity and healthcare costs caused by persistent HPV infection, so long as problems besetting current modest vaccination rates are better understood and overcome. The proposed study will examine factors that differentially relate to clinicians'stated intentions to administer HPV vaccine, using new measures of intentionality and clinicians'evaluative perceptions of professional recommendations. Our work will help inform future research and the design of strategies to improve the likelihood that physicians would adopt recommendations for administering HPV vaccine.